change codes-examples to tutorials (root-project#369)

* change codes-examples to tutorials

* fix wrong link

Author: couet

_data/navigation.yml

@@ -229,5 +229,5 @@ start:
      children:
       - title: Courses
         url: get_started/courses
-      - title: Code Examples
-        url: get_started/code_examples
+      - title: Tutorials
+        url: tutorials

get_started/code_examples.md

@@ -18,7 +18,7 @@ different, more direct approach to the ROOT fundamental
 concepts as well as some hands-on exercise. In order to integrate the information present
 in the aforementioned sources, [this collection of ROOT courses](courses){:target="_blank"}
 is definitively useful. Once the fundamental concepts have been acquired, a rich set of
-[code examples]({{ '/get_started/code_examples' | relative_url }}) are available to dive into the code.
+[tutorials]({{ '/tutorials' | relative_url }}) are available to dive into the code.
 
 Remember, you can always resort to the
 [ROOT Forum](https://root-forum.cern.ch){:target="_blank"}

get_started/index.md

@@ -2,19 +2,28 @@
 title: Tutorials
 layout: single
 sidebar:
-  nav: "manual"
+  nav: "start"
 ---
 
-ROOT offers a rich set of code examples that allow you to see ROOT's building blocks "in
-action", as part of more complex programs. They are separated in two categories: C++ or
-python scripts and Jupyter notebooks.
+ROOT offers a rich set of tutorials that allow you to see ROOT's building blocks "in action",
+as part of more complex programs. They are separated in two categories: C++ or python scripts
+and Jupyter notebooks.
 
 The tutorials are available for all major ROOT releases.
-**[These](https://root.cern/doc/master/group__Tutorials.html){:target="_blank"}** are the links
-for the latest
-git snapshot. All scripts are available also in the form of a **ROOTBook** which can be
-visualized in
-[NBViewer](https://nbviewer.jupyter.org/){:target="_blank"} or tried out interactively in
-[SWAN](https://swan.web.cern.ch/){:target="_blank"}.
-Just look for these badges: <img src="{{'/assets/images/notebook.gif' | relative_url}}" style="height:1em"> <img src="{{'/assets/images/badge_swan_white_150.png' | relative_url}}" style="height:1em">
+**[These](https://root.cern/doc/master/group__Tutorials.html){:target="_blank"}** are the links for their
+latest version. Most tutorials are also available as ROOTBook which can
+be visualized in [NBViewer](https://nbviewer.jupyter.org/){:target="_blank"} or tried interactively in
+[SWAN](https://swan.web.cern.ch){:target="_blank"}. Such tutorials are marked with these badges:
+<img src="https://root.cern/doc/master/notebook.gif" alt="View in nbviewer" style="height:1em">
+<img src="https://swanserver.web.cern.ch/swanserver/images/badge_swan_white_150.png" alt="Open in SWAN" style="height:1em">
 
+Once you have [properly setup the ROOT environment]({{'manual/first_steps_with_root' | relative_url }}){:target="_blank"},
+all the tutorials will be available on *your* machine in the `$ROOTSYS/tutorials` folder.
+You can then [execute/read the macros]({{'manual/first_steps_with_root/#root-macros' | relative_url }})
+there to learn from the examples. Do not hesitate to comment out/ add code to these tutorials
+macros to learn interactively how ROOT works.
+Among the long list of tutorials you may want to start with:
+[histograms](https://root.cern/doc/master/group__tutorial__hist.html){:target="_blank"},
+[graphs](https://root.cern/doc/master/group__tutorial__graphs.html){:target="_blank"},
+[graphics](https://root.cern/doc/master/group__tutorial__graphics.html){:target="_blank"} and
+[trees](https://root.cern/doc/master/group__tutorial__tree.html){:target="_blank"}.